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R.g. Paredes - One of the best experts on this subject based on the ideXlab platform.
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infusions of naloxone into the Medial Preoptic Area ventroMedial nucleus of the hypothalamus and amygdala block conditioned place preference induced by paced mating behavior
Hormones and Behavior, 2008Co-Authors: Patricia S Garciahorsman, Anders ǻgmo, R.g. ParedesAbstract:Paced mating induces positive affect as revealed by conditioned place preference (CPP) in female rats. It has been suggested that endogenous opioids are involved in the generation of this positive affect since systemic administration of the opioid antagonist naloxone blocks mating-induced CPP. Several brain structures, including the Medial Preoptic Area (mPOA), the ventroMedial nucleus of the hypothalamus (VMH), the amygdala (Me), and the nucleus accumbens (Acb) have been implicated in the control of female sexual behavior. However, it is not known if these structures also participate in the positive affect produced by paced mating. To this end we determined the effects of intracranial administration of naloxone methiodide into the mPOA, VMH, Me and Acb on conditioned place preference induced by paced mating in female rats. Regardless of the site of infusion 5 μg of naloxone did not affect any of the sexual behavior parameters measured during copulation. When CPP was evaluated, the groups infused with naloxone into the mPOA, the VMH, and the Me before each conditioning session did not develop place preference. Only the group infused with naloxone in the Acb and the control groups did so. These results demonstrate that opioid receptors within the mPOA, VMH and Me are necessary for the rewarding aspects of paced mating. We suggest that the Me and VMH are important for the transmission of sensory information produced by copulation while the mPOA is the site where the positive affect is originated.
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inactivation of the Medial Preoptic Area anterior hypothalamus by lidocaine reduces male sexual behavior and sexual incentive motivation in male rats
Neuroscience, 2008Co-Authors: H.a. Hurtazo, R.g. Paredes, Anders AgmoAbstract:Permanent bilateral lesions of the Medial Preoptic Area anterior hypothalamus (MPOA/AH) produce a drastic inhibition of male sexual behavior in all species studied to date. The present experiment was designed to evaluate if temporal inactivation of the MPOA/AH by infusions of lidocaine also inhibits sexual behavior in male rats. This would allow us to rule out the possibility that the behavioral effects observed after damage of the MPOA/AH could be associated with plastic changes induced by the lesion in other brain regions. We also evaluated sexual incentive motivation in males after the infusion of lidocaine in a test in which copulation is not possible but where males maintain approach behavior to the estrous females despite repeated testing. The percentage of animals displaying mounts, intromissions and ejaculation was significantly reduced while mount and intromission latency were prolonged after infusion of lidocaine. No changes were observed in sexual behavior after infusion of lidocaine in animals with cannulae outside the MPOA/AH suggesting that the inhibitory effects are specific to this brain region. Sexual incentive motivation was also affected by administration of lidocaine. Males consistently showed a clear preference for the sexually receptive female except when infused with lidocaine. After the infusion of the compound a significant reduction in the time spent in the incentive zone of the stimulus female was observed. These results support the hypothesis that neurons of the MPOA/AH are involved in the control of male sexual motivation.
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Olfactory preference and Fos expression in the accesory olfactory system of male rats with bilateral lesions of the Medial Preoptic Area/anterior hypothalamus
Neuroscience, 2005Co-Authors: H.a. Hurtazo, R.g. ParedesAbstract:In the present study we evaluated if a Medial Preoptic Area/anterior hypothalamus lesion affects the olfactory preference toward soiled bedding from receptive females in comparison to bedding from anestrous females or clean bedding. In the second part of the study we evaluated the accessory olfactory system response to estrous bedding with Fos immunoreactivity to determine if the Preoptic lesions modify the processing of sexually relevant olfactory cues. Before Medial Preoptic Area/anterior hypothalamus lesions, male rats spent more time investigating estrous bedding as opposed to anestrous or clean bedding. After the lesion, subjects showed no preference between estrous and anestrous bedding; that is, males spent the same amount of time investigating both types of bedding. These two odors were investigated more than clean bedding. Increments in Fos immunoreactivity neurons were seen in structures of the accessory olfactory system after exposure to soiled estrous bedding [granular layer of the accessory olfactory bulb, anterior-dorsal Medial amygdala, posterior-dorsal Medial amygdala, bed nucleus of the stria terminalis]. These results suggest that bilateral destruction of the Medial Preoptic Area/anterior hypothalamus modify male olfactory preference in such a way that subjects spend the same time smelling and investigating bedding from estrous and anestrous females. This change in olfactory preference is not associated with alterations in the processing of sexually relevant olfactory cues by the accessory olfactory system.
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Medial Preoptic Area anterior hypothalamus and sexual motivation
Scandinavian Journal of Psychology, 2003Co-Authors: R.g. ParedesAbstract:The Medial Preoptic Area/anterior hypothalamus (MPOA/AH) is a brain site derived from proliferative zones from the diencephalon and telencephalon. It is probably this characteristic that makes this brain region participate in different physiological and behavioral functions. The present review addresses the role of the MPOA/AH in the control of male sexual behavior. It is clear that the MPOA/AH is a crucial site in the control of sexual behavior in males of all species studied to date. But although many different publications have followed the contribution of Heimer and Larsson there is no agreement as to what is specifically the role of the MPOA/AH in sexual behavior. At least three hypotheses have been presented. The first one suggests that this brain region is involved in the consummatory aspects (execution) of sexual behavior. The second indicates that the MPOA/AH is involved in the appetitive components (motivation) of masculine sexual behavior. The third hypothesis considers that MPOA/AH neurons are involved in the regulation of consummatory and appetitive aspects of sexual behavior. From the literature reviewed, it will become evident that the evidence supporting a role of the MPOA/AH in the execution of sexual behavior is based on a number of limited studies not easy to interpret. On the other hand, several lines of evidence using a variety of methodologies support the notion that the MPOA/AH is involved in the motivational aspects of male sexual behavior.
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lesions of the Medial Preoptic Area anterior hypothalamus mpoa ah modify partner preference in male rats
Brain Research, 1998Co-Authors: R.g. Paredes, Tanya Tzschentke, Nancy NakachAbstract:When given the choice, male rats will interact with a receptive female while female rats will interact with a sexually active male. In the present experiment partner preference was tested in male and female rats before and after lesions of the Medial Preoptic Area of the anterior hypothalamus (MPOA/HA). Subjects were gonadectomized, treated for 10 days with 5 μg/kg of estradiol benzoate (EB) and tested for male coital behavior with receptive females and for partner preference in a three compartment box with free access to either a sexually receptive female or a sexually active male. The same tests were repeated after 10 days of treatment with 5 mg/kg of testosterone propionate (TP). The subjects then received a bilateral electrolytic lesion aimed at the MPOA/AH. Two weeks after the lesion the hormonal treatments and behavioral tests were repeated in the same sequence. Prior to the lesion, females showed a clear preference to interact with the stimulus male while male subjects showed a preference to interact with the receptive female regardless of the hormonal treatment they received. After lesions the females preference for the opposite sex was not modified, they spent more time in the chamber with the stimulus male regardless of whether they had an extensive bilateral destruction of the MPOA/AH or a sham lesion. Males with bilateral destruction of the MPOA/AH changed their partner preference after the lesion. They spent significantly more time in the chamber with the stimulus male than in the chamber with the receptive female. As well, the coital behavior of males with bilateral destruction of the MPOA/AH was significantly reduced after the lesion. The change of preference was observed when the lesioned animals were treated either with EB or TP. The results of the present experiment further support the notion that the MPOA/AH is a crucial structure in the integration of sensory cues that determine partner preference.
Stefania Stanzani - One of the best experts on this subject based on the ideXlab platform.
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Branching projections of ventrolateral reticular neurons to the Medial Preoptic Area and lumbo-sacral spinal cord
Behavioral and brain functions : BBF, 2005Co-Authors: Antonella Russo, Rosa Romeo, Rosalia Pellitteri, Stefania Stanzani, André JeanAbstract:Different findings indicate that rostral ventrolateral reticular nucleus (RVL) is neuronal substrate of integration and regulation of the cardiovascular functions. Some efferent RVL neurons project to the thoraco-lumbar spinal cord and excite preganglionic sympathetic neurons, to the spinal phrenic motor neurons involved in inspiratory function and increase the activity of vasoconstrictor fibres innervating blood vessels in the skin and skeletal muscle. Our study was aimed at revealing presence of neurons within RVL supplying branching collateral input to the Medial Preoptic Area (MPA) and to the lumbo-sacral spinal cord (SC-L) in the rat. All animal experiments were carried out in accordance with current institutional guidelines for the care and use of experimental animals. We have employed double fluorescent-labelling procedure: the projections were defined by injections of two retrograde tracers: Rhodamine Labelled Bead (RBL) and Fluoro Gold (FG) in the MPA and SC-L, respectively. Our results showed the presence of few single FG neurons and single RBL neurons in the RVL. The size of FG-neurons and RBL-neurons was medium (25–30 μm) and large (50 μm). Few double-projecting neurons were distributed in the middle third of RVL nucleus, their size was 30–40 μm. The results demonstrate that pools of neurons in the RVL have collateral projections to the MPA and SC-L and they are involved in ascending and descending pathway. These data suggest that these neurons could play a role in maintaining activity of central and peripheral blood flow.
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Serotonergic collateralized projections from Barrington's nucleus to the Medial Preoptic Area and lumbo-sacral spinal cord.
Brain research, 2004Co-Authors: Antonella Russo, Sebastiana Monaco, Rosa Romeo, Rosalia Pellitteri, Stefania StanzaniAbstract:In this study, we employed triple fluorescent labelling to reveal the distribution of the direct serotonergic neurons within Barrington's nucleus (BN) that supply branching collateral input to the Medial Preoptic Area (MPA) and to the lumbo-sacral spinal cord (LSC). Immunocytochemical detection of the monoclonal antibody raised against serotonin was used for identification of the neurons. The projections were defined by injections of two retrograde tracers: fluoro gold and rhodamine in the MPA and LSC, respectively. The aim of this study is to identify the direct projections to BN and MPA and/or LSC. The present study confirms findings of others describing BN-LSC projections and extends previous findings by demonstrating an single or collateralized fibers with MPA, and serotonergic immunoreactive fibers.
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branching serotonergic and non serotonergic projections from caudal brainstem to the Medial Preoptic Area and the lumbar spinal cord in the rat
Neuroscience Letters, 1995Co-Authors: Giampiero Leanza, Rosalia Pellitteri, S Perez, Alessandra Russo, Stefania StanzaniAbstract:Abstract The distribution and the chemical identity of retrogradely single and double labeled neurons in the caudal raphe nuclei were analyzed in the rat following injection of two fluorescent tracers into the Medial Preoptic Area and the ventral/intermediate grey of the lumbar spinal cord, and serotonin immunocytochemistry. The results suggest that (1) neurons in the caudal raphe nuclei exhibit highly collateralized axons, able to simultaneously innervate rostrally- and caudally-located targets; (2) a large proportion (40–50%) of the raphe-spinal projection does not contain serotonin, which by contrast is present in more than 70% of the neurons projecting to the Medial Preoptic Area; (3) only a small fraction of the observed collateralized projection is serotonergic. Thus, multiple transmitter systems are likely to be involved in the diffuse ascending and descending influence arising from these nuclei.
Elaine M. Hull - One of the best experts on this subject based on the ideXlab platform.
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influences of dopamine and glutamate in the Medial Preoptic Area on male sexual behavior
Pharmacology Biochemistry and Behavior, 2014Co-Authors: Ryan G Will, Elaine M. Hull, Juan M DominguezAbstract:Abstract Several brain nuclei interact to orchestrate the appetitive and consummatory aspects of male sexual behavior. Of these structures, the Medial Preoptic Area (mPOA) of the hypothalamus is of particular interest, as it receives input from all sensory modalities, and damage to this region disrupts copulation in a wide variety of taxa. Furthermore, the mPOA is both responsive to gonadal hormones and involved in endocrine regulation. Neurochemical studies have demonstrated that both dopamine and glutamate levels rise in the mPOA in response to sexual activity, while antagonism of these neurotransmitters impairs male sexual response. Here we review how dopamine and glutamate act in the mPOA to modulate male sexual behavior.
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Dopamine Release in the Medial Preoptic Area of Female Rats in Response to Hormonal Manipulation and Sexual Activity
2013Co-Authors: Leslie Matuszewich, Daniel S. Lorrain, Elaine M. HullAbstract:Dopamine (DA) is responsive to hormonal manipulations and has been implicated in the regulation of female rat sexual behavior. In the present studies, extracellular DA levels were assessed in the Medial Preoptic Area (MPOA) of ovariectomized female rats in response to exogenous ovarian hormones and during sexual activity. In female rats primed with a low dose of estradiol benzoate (2 jxg), but not with a higher dose (20 /xg), a 500-/zg progesterone injection increased extraceUular DA and facilitated copulatory behavior. Extracellular DA levels in the MPOA were further augmented during sexual interactions with a male rat in a nonpacing copulatory chamber by either perineal or vaginal stimulation. However, in a pacing chamber, DA efflux did not increase, although the metabolites rose significantly during copulation. Together, these findings suggest that extracellular DA in the MPOA responds to the hormonal state of the female rat and may contribute to her expression of sexual behavior. Although much research has established hypothalamic and midbrain structures as critical to the regulation of female rat receptive and proceptive behaviors (see Pfaff, Schwartz-Giblin, McCarthy, & Kow, 1994), the contribution of forebrain regions, including the Medial Preoptic Area (MPOA), remains to be elucidated. Previous studies have suggested that the MPOA may inhibit the receptive posture, lordosis. Electrolytic lesions of the MPOA increased the lordosis response during copulation in hormonally primed femal
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oxytocin in the Medial Preoptic Area facilitates male sexual behavior in the rat
Hormones and Behavior, 2011Co-Authors: Renu Bhatt, Katie B Picotte, Elaine M. HullAbstract:Oxytocin (OT) is a versatile neuropeptide that is involved in a variety of mammalian behaviors, and its role in reproductive function and behavior has been well established. The majority of pharmacological studies of the effects of OT on male sexual behavior have focused on the paraventricular nucleus (PVN), ventral tegmental Area (VTA), hippocampus, and amygdala. Less attention has been given to the Medial Preoptic Area (MPOA), a major integrative site for male sexual behavior. The present study investigated the effects of intra-MPOA administration of OT and (d(CH2)51, Tyr(Me)2, Thr4, Orn8, Tyr-NH29)-vasotocin, an OT antagonist (OTA), on copulation in the male rat. The relationship between OT receptor (OTR) binding levels in the MPOA and sexual efficiency was also explored. Microinjection of OT into the MPOA facilitated copulation in sexually experienced male rats, whereas similar injections of an OTA inhibited certain aspects of copulation but had no significant effect on locomotor activity in an open field. Contrary to expectation, sexually efficient males had lower levels of OTR binding in the rostral MPOA compared to inefficient animals. The present data suggest that OT activity in the MPOA is not necessary for the expression of male sexual behavior but is sufficient to facilitate copulatory behaviors and improve sexual efficiency in sexually experienced male rats. These data also suggest that OTR activity in the MPOA stimulates anogenital investigation, facilitates the initiation of copulation, and plays a role in the sensitization effect of the first ejaculation on subsequent ejaculations.
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dopamine the Medial Preoptic Area and male sexual behavior
Physiology & Behavior, 2005Co-Authors: Juan M Dominguez, Elaine M. HullAbstract:The Medial Preoptic Area (MPOA), at the rostral end of the hypothalamus, is important for the regulation of male sexual behavior. Results showing that male sexual behavior is impaired following MPOA lesions and enhanced with MPOA stimulation support this conclusion. The neurotransmitter dopamine (DA) facilitates male sexual behavior in all studied species, including rodents and humans. Here, we review data indicating that the MPOA is one site where DA may act to regulate male sexual behavior. DA agonists microinjected into the MPOA facilitate sexual behavior, whereas DA antagonists impair copulation, genital reflexes, and sexual motivation. Moreover, microdialysis experiments showed increased release of DA in the MPOA as a result of precopulatory exposure to an estrous female and during copulation. DA may remove tonic inhibition in the MPOA, thereby enhancing sensorimotor integration, and also coordinate autonomic influences on genital reflexes. In addition to sensory stimulation, other factors influence the release of DA in the MPOA, including testosterone, nitric oxide, and glutamate. Here we summarize and interpret these data.
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extracellular dopamine in the Medial Preoptic Area implications for sexual motivation and hormonal control of copulation
The Journal of Neuroscience, 1995Co-Authors: Elaine M. Hull, Daniel S. Lorrain, Jianfang Du, Leslie MatuszewichAbstract:Dopamine (DA) activity in the Medial Preoptic Area (MPOA) contributes to the control of male rat sexual behavior. We tested (1) whether extracellular DA increases during precopulatory exposure to an estrous female and during copulation, (2) whether exposure to another male increases extracellular DA, (3) whether motor activity during copulation accounts for increased DA levels, and (4) whether concurrent or recent testosterone influences DA levels or copulation in castrates. Extracellular DA and its metabolites in male rats9 MPOA were measured using microdialysis. DA level increased during precopulatory exposure to the female in all animals that subsequently copulated; this included all intact animals, all testosterone-treated castrates, and 9 of 14 1- week castrates treated with oil vehicle. DA levels did not increase in any animal that subsequently failed to copulate, including the remaining 1-week, and all 2-week, vehicle-treated castrates. When the barrier was removed and the animals were allowed to copulate, levels of DA and its metabolites continued to rise in intact males and in castrates that copulated. The DA response to the estrous female could not be attributed to nonsexual social stimuli, since exposure to another male was ineffective. The DA response to copulation could not be attributed primarily to motor activity, since animals running voluntarily in a running wheel did not show significantly increased DA. These and previous data suggest that DA released in the MPOA in response to an estrous female may contribute to sexual motivation and copulatory proficiency. Testosterone may promote copulation in part through permissive actions on dopamine release.
Rosalia Pellitteri - One of the best experts on this subject based on the ideXlab platform.
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Branching projections of ventrolateral reticular neurons to the Medial Preoptic Area and lumbo-sacral spinal cord
Behavioral and brain functions : BBF, 2005Co-Authors: Antonella Russo, Rosa Romeo, Rosalia Pellitteri, Stefania Stanzani, André JeanAbstract:Different findings indicate that rostral ventrolateral reticular nucleus (RVL) is neuronal substrate of integration and regulation of the cardiovascular functions. Some efferent RVL neurons project to the thoraco-lumbar spinal cord and excite preganglionic sympathetic neurons, to the spinal phrenic motor neurons involved in inspiratory function and increase the activity of vasoconstrictor fibres innervating blood vessels in the skin and skeletal muscle. Our study was aimed at revealing presence of neurons within RVL supplying branching collateral input to the Medial Preoptic Area (MPA) and to the lumbo-sacral spinal cord (SC-L) in the rat. All animal experiments were carried out in accordance with current institutional guidelines for the care and use of experimental animals. We have employed double fluorescent-labelling procedure: the projections were defined by injections of two retrograde tracers: Rhodamine Labelled Bead (RBL) and Fluoro Gold (FG) in the MPA and SC-L, respectively. Our results showed the presence of few single FG neurons and single RBL neurons in the RVL. The size of FG-neurons and RBL-neurons was medium (25–30 μm) and large (50 μm). Few double-projecting neurons were distributed in the middle third of RVL nucleus, their size was 30–40 μm. The results demonstrate that pools of neurons in the RVL have collateral projections to the MPA and SC-L and they are involved in ascending and descending pathway. These data suggest that these neurons could play a role in maintaining activity of central and peripheral blood flow.
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Serotonergic collateralized projections from Barrington's nucleus to the Medial Preoptic Area and lumbo-sacral spinal cord.
Brain research, 2004Co-Authors: Antonella Russo, Sebastiana Monaco, Rosa Romeo, Rosalia Pellitteri, Stefania StanzaniAbstract:In this study, we employed triple fluorescent labelling to reveal the distribution of the direct serotonergic neurons within Barrington's nucleus (BN) that supply branching collateral input to the Medial Preoptic Area (MPA) and to the lumbo-sacral spinal cord (LSC). Immunocytochemical detection of the monoclonal antibody raised against serotonin was used for identification of the neurons. The projections were defined by injections of two retrograde tracers: fluoro gold and rhodamine in the MPA and LSC, respectively. The aim of this study is to identify the direct projections to BN and MPA and/or LSC. The present study confirms findings of others describing BN-LSC projections and extends previous findings by demonstrating an single or collateralized fibers with MPA, and serotonergic immunoreactive fibers.
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branching serotonergic and non serotonergic projections from caudal brainstem to the Medial Preoptic Area and the lumbar spinal cord in the rat
Neuroscience Letters, 1995Co-Authors: Giampiero Leanza, Rosalia Pellitteri, S Perez, Alessandra Russo, Stefania StanzaniAbstract:Abstract The distribution and the chemical identity of retrogradely single and double labeled neurons in the caudal raphe nuclei were analyzed in the rat following injection of two fluorescent tracers into the Medial Preoptic Area and the ventral/intermediate grey of the lumbar spinal cord, and serotonin immunocytochemistry. The results suggest that (1) neurons in the caudal raphe nuclei exhibit highly collateralized axons, able to simultaneously innervate rostrally- and caudally-located targets; (2) a large proportion (40–50%) of the raphe-spinal projection does not contain serotonin, which by contrast is present in more than 70% of the neurons projecting to the Medial Preoptic Area; (3) only a small fraction of the observed collateralized projection is serotonergic. Thus, multiple transmitter systems are likely to be involved in the diffuse ascending and descending influence arising from these nuclei.
Antonella Russo - One of the best experts on this subject based on the ideXlab platform.
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Branching projections of ventrolateral reticular neurons to the Medial Preoptic Area and lumbo-sacral spinal cord
Behavioral and brain functions : BBF, 2005Co-Authors: Antonella Russo, Rosa Romeo, Rosalia Pellitteri, Stefania Stanzani, André JeanAbstract:Different findings indicate that rostral ventrolateral reticular nucleus (RVL) is neuronal substrate of integration and regulation of the cardiovascular functions. Some efferent RVL neurons project to the thoraco-lumbar spinal cord and excite preganglionic sympathetic neurons, to the spinal phrenic motor neurons involved in inspiratory function and increase the activity of vasoconstrictor fibres innervating blood vessels in the skin and skeletal muscle. Our study was aimed at revealing presence of neurons within RVL supplying branching collateral input to the Medial Preoptic Area (MPA) and to the lumbo-sacral spinal cord (SC-L) in the rat. All animal experiments were carried out in accordance with current institutional guidelines for the care and use of experimental animals. We have employed double fluorescent-labelling procedure: the projections were defined by injections of two retrograde tracers: Rhodamine Labelled Bead (RBL) and Fluoro Gold (FG) in the MPA and SC-L, respectively. Our results showed the presence of few single FG neurons and single RBL neurons in the RVL. The size of FG-neurons and RBL-neurons was medium (25–30 μm) and large (50 μm). Few double-projecting neurons were distributed in the middle third of RVL nucleus, their size was 30–40 μm. The results demonstrate that pools of neurons in the RVL have collateral projections to the MPA and SC-L and they are involved in ascending and descending pathway. These data suggest that these neurons could play a role in maintaining activity of central and peripheral blood flow.
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Serotonergic collateralized projections from Barrington's nucleus to the Medial Preoptic Area and lumbo-sacral spinal cord.
Brain research, 2004Co-Authors: Antonella Russo, Sebastiana Monaco, Rosa Romeo, Rosalia Pellitteri, Stefania StanzaniAbstract:In this study, we employed triple fluorescent labelling to reveal the distribution of the direct serotonergic neurons within Barrington's nucleus (BN) that supply branching collateral input to the Medial Preoptic Area (MPA) and to the lumbo-sacral spinal cord (LSC). Immunocytochemical detection of the monoclonal antibody raised against serotonin was used for identification of the neurons. The projections were defined by injections of two retrograde tracers: fluoro gold and rhodamine in the MPA and LSC, respectively. The aim of this study is to identify the direct projections to BN and MPA and/or LSC. The present study confirms findings of others describing BN-LSC projections and extends previous findings by demonstrating an single or collateralized fibers with MPA, and serotonergic immunoreactive fibers.